Impregnated cigarette



Patented Sept. 14, 1937 UNITED STATES PATENT OFFICE IMPREGNATEDCIGARETTE No Drawing. Application May 18, 1935, Serial No. 22,167

7 Claims.

This invention relates to the manufacture of cigarettes and moreparticularly to a method of treating the paper of the cigarette. torender the same waterproof and at the same time not to impair thesmoking qualities of the finished cigarette.

It is well known that paper which is commonly used in the manufacture ofcigarettes has the disadvantage that it readily disintegrates when itbecomes wet or damp for any reason. The paper also has a definitetendency to stick to the lips, sometimes quite tenaciously. It is acommon experience of smokers to have a cigarette become soggy due to theabsorption of moisture by the paper and tobacco and to have theindividual pieces of tobacco become loosened and remain in the mouth.Heretofore, these disadvantages have been partly overcome by coating onetip of the cigarette with straw, cork, bark, ivory, and materials of asimilar nature. The main disadvantages of this practice are that thecost of cigarettes so prepared is high because of the special tippingoperation required; the cigarette can be lighted at only one end; andonly the tip is protected and rain or wet fingers readily cause theremaining part of the cigarette to disintegrate rapidly. Otherexpedients such as coating the cigarette or cigarette paper withcellulose derivatives, oils, waxes, etc. have been proposed, but in eachcase the appearance, burning rate, odor, or taste has been adverselyinfluenced by the agent used.

The use of various resins for coating cigarette paper has also beenproposed. It has been my experience, however, that the resins suggestedin the prior art exert a more or less definite and undesirabletransparentizing action on the paper, thereby altering its appearance.Apparently it is possible to obviate this transparentizing eifect byapplying the resin in such a way as to produce an efllorescent coatingon the paper, but this method is commercially undesirable because itinvolves the costly process of drying the paper, after it has beentreated with a solution of the resin in organic solvent, in special andabnormal- 1y warm, humid atmospheres, in order to produce this bloomingor blushing effect which masks the transparentizing action of the resin.

This invention has as an object the preparation of a cigarette which isresistant to moisture, at least over that part which is placed in themouth and preferably over its entire length. A further object is thepreparation of cigarette paper or the impregnation of the paper of afinished cigarette, without the necessity of resorting to spethe sametime will not have adversely ailected its appearance, odor, taste, orcombustibility.

These object'sare accomplished by treating the cigarette paper before orafter the cigarette is made with dilute solutions or emulsions ofcertain synthetic resins not heretofore to my knowledge proposed for thepurpose. The resins used in my invention are of the type which do nottransparentize the paper; that is, they do not give the paperimpregnated therewith the appearance of parchment but leave it inexactly the same condition, as far as may be observed, as the originalpaper. Furthermore, these eflects are secured without resorting tospecial solvents or special methods of drying.

It has been found that only limited and restricted classes of syntheticresins have the properties described above. Those with which the presentinvention is concerned are the polymeric esters of u-methylenecarboxylic acids. This expression comprehends the mono or polyhydricalcohol or phenol esters of mono or polycarboxylic acids having amethylene group (=CH2) attached to a carbon atom adjacent to a carboxylgroup. Within this field, the most generally useful agents are resinouspolymers of compounds of the general formula where R is hydrogen or amonovalent hydrocarbon radical and R1 is a monovalent organic radicalderived from a monohydric alcohol by removal of the hydroxyl therefrom.R1 may be the radical of a saturated or unsaturated, straight orbranched chain, aliphatic, alicyclic or aromatic alcohol, which alcoholmay or may not contain other groups such as ketone, ether, amino, etc.The following specific resins, derived from compounds of the abovegeneral formula, may be used in the practice of this invention: methylalpha-methacrylate (the outstanding resin), cyclohexylalpha-methacrylate, isobutyl alpha-methacrylate, ethylalpha-methacrylate, methyl acrylate, isopropyl acrylate,diethylaminoethyl alpha-methacryl-ate, ethoxyethyl alpha-methacrylate,benzyl alpha-methacrylate ethyl alphaethacrylate, methylalpha-phenacrylate, methyl alpha-cyclohexyl arcrylate, etc. Other estersof a-methylene carboxylic acids whose polymers may be used in thisinvention are diethyl itaconate and other esters of itaconicacid. I mayalso use in my invention interpolymers or mixtures of polymers ofdifferent esters of e-methylene carboxylic acids.

The following examples be carried out. However, the practice of theinvention is not limited to the examples since modifications thereofwill be readily apparent to those skilled in the art.

This solution was brushed on approximately inch of the tip of acigarette with a small camel's hair brush. The solution penetrated thepaper and within one minute at approximately 25 C. the treated paper tipwas perfectly dry and no different in appearance from the remainder ofthe cigarette. The treated tip was waterproofed to the extent that itcould be rubbed between moist lips without any effect on the paper and adefinite line of demarcation existed between the treated and untreatedportions of the cigarette when moistened by the tongue or lips.

The cigarette maybe rendered waterproof over its entire length bybrushing the above resin solution over the remainder of the cigarette.

Example: II

Parts Methyl methacrylate polymer 0.5 Toluene 99.5

100.0 Example III Parts Methyl methacrylate polymer 1.5 Butyl acetat20.0 Acetone 77.5 Dibutyl phthalate -1.0

100.0 Example IV Parts Cyclohexyl methacrylate polymer 2 Xylene 3Petroleum ether 20 Ethyl acetate 75 Example V Parts 25% methylacrylate'l5% methyl methacrylate interpolymer 2 Butyl acetate 10 Acetone88 100 Example VI Parts Diethyl itaconate polymer 2.5 Butyl acetate 14.0Acetone 83.5

Cigarettes treated with a solution prepared according to any one of theabove examples are rendered definitely waterproof and at the same timeno difference between these and untreated cigarettes may be detected inrespect in which parts given are by weight, illustrate how the inventionmay to odor, taste, appearance, and rate of burning.

In connection with this latter test, 'two cigarettes, one which had beentreated and the other which had not been treated, were lighted andsmoked for about 4 inch and then laid side by side at the edge of atable. The cigarettes burned at the same rate and there was no evidenceto indicate that the coatings had any effect whatever on thecombustibility or burning qualities of the cigarettes. In Example IIIgiven above, it willbe noted that dibutyl phthalate has been added tothe resin solution. A plasticizing agent of this type may be added whereincreased piiability of the treated paper is desired or where the resinis friable. It will be readily apparent that the amount of plasticizingagent may be increased or decreased to obtain the results desired; and,further, no limitation is placed on the particular plasticizer which maybe used other than the fact that it must not be poisonous or have anoffensive odor.

While I have given examples where the resin is dissolved, I may resortto aqueous emulsions particularly where the coating is applied to thepaper before it is made into a cigarette. The expense and fire andhealth hazards of handling organic solvents are thus avoided. Unlikesolutions, emulsions do not vary greatly in viscosity with differentresins and difierent concentrations and as a result lend themselves morereadily to application in one operation of the same amount of difierentresins or different amounts of the same resin.

In the practice of this invention it is preferable to use dilutesolutions or emulsions, for example in the range from 0.5 to 2.5% resinby weight. This concentration may, however, be varied beyond theselimits. For example, if a resin of very low viscosity is used or if thesolvent selected is particularly active, the percentage of resin may beincreased. On the other hand, the solution may be made as thin asdesired but if carried too far in this direction, a plurality ofimpregnations or coatings will probably be necessary. Pigmentedcompositions may in some instances be used to advantage. It has alsobeen found that in addition to solvent, resin, and plasticizer, smallamounts of cellulose derivatives such as cellulose nitrate, celluloseacetate, ethyl cellulose and other esters and ethers may be incorporatedinto the impregnating compositions. These compounds should be added,however, in amounts small enough so that they will not seriouslyinfluence the rate of burning or taste of the cigarette.

While I have indicated that the resin solution may be brushed on thepaper of the cigarette, it is obvious that other conventional methodsmay be used such as spraying or dipping. It is also within the scope ofthis invention to treat the cigarette paper with the resin before thecigarette is rolled by dipping the paper in the resin solution oremulsion, or by applying the resin to one side or both sides of thepaper. The untreated cigarette may also be passed over rolls one side ofwhich is immersed in the resin solution or emulsion.

I believe that the unaltered appearance of my I coated cigarettes is dueto the fact that the resins indices such as 1.515, 1.54 and 1.64. Therefractive index of cigarette papers ranges from 1.53 upwards. Theresins which I use, however, have values of around 1.47 and. 1.18. Theobjects of this invention can therefore be accomplished by theemployment of any synthetic resin which has a refractive indexsubstantially lower than that of the cigarette paper.

It is apparent that many widely difierent em-- bodiments of thisinvention may be made without departing from the spirit and scopethereof;

and, therefore, it is not intended to be limitedinous polymer of acompound having the formula where R is a member of the group composed ofhydrogen and a monovalent hydrocarbon radical and. R1 is a monovalentorganic radical derived from a monohydric alcohol by removal of thehydroxyl therefrom.

3. A cigarette having the paper thereof treated with a compositioncomprising essentially a resinous polymer of methyl alpha-methacrylate.

4. In the manufacture of cigarettes the step which comprises treatingthe cigarette paper with a composition comprising essentially a resinouspolymeric ester of an alpha-methylene carboxylic acid.

5. In the manufacture of cigarettes, the step which comprises treatingthe cigarette paper with a composition containing 0.5-2.5% of a resinouspolymeric ester of an alpha-methylene carboxylic acid.

6. In the manufacture of cigarettes the step which comprises treatingthe cigarette paper with a composition containing 05-25% of a resinouspolymer of a compound of the general formula where R is a member of thegroup composed of hydrogen and a monovalent hydrocarbon radical and R1is a monovalent organic radical derived from a monohydric alcohol byremoval of the hydroxyl therefrom. I

'7. In the manufacture of cigarettes the step which comprises treatingthe cigarette paper with a composition containing 0.5-2.5% of methylalpha-methacrylate ,resin.

- DANIEL E. STRAIN.

